Four Salafists were killed in renewed clashes with Shiite Zaidi rebels in northern Yemen on Saturday, the second straight day of deadly fighting, tribal sources.
The four men died in the town of Reda, in Amran province where tribesmen said a Salafist was killed on Friday in clashes with Zaidi rebels.
There were no immediate reports of casualties on the Zaidi side.
But witnesses said Zaidi rebels on Saturday shelled a mosque in Reda and blew up a Koranic school, adding that fighting rocked the town for several hours.
The confrontations first erupted on Friday as Salafists and tribesmen tried to prevent a Zaidi protest against administrative appointments in their regions.
The two sides, armed with rocket-propelled grenades, brought in reinforcements and the situation was tense in the city, witnesses said.
Residents said tensions escalated after the appointment of supporters of the Islamist party Al-Islah to head Yemen's northern provinces, a move rejected by the Zaidis.
The clashes come ahead of a national dialogue scheduled for later this year as part of a political agreement that led to the February departure of president Ali Abdullah Saleh following a year of unrest. Zaidi rebels have indicated they would take part in the dialogue.
Dozens of people have been killed since last year in sectarian clashes between the rebels and Sunni Salafists trying to tighten their grip on northern Yemen, in the absence of government control.
Zaidis make up a minority in the Sunni-majority country.